Effect of Mn Incorporated into LiNbO₃ Crystal Structure on the Electronic and Optical Properties Using First-Principles Study

Abstract

The structural, electronic and optical properties of lithium niobate (LiNbO3) and manganese (Mn)-doped LiNbO3 are investigated using a first-principles study. The first-principles calculation in this work is implemented using CASTEP computer code with GGA-PBE correlation. The band structure and density of states are calculated to analyze the effect of Mn doping on the electronic properties of LiNbO3. Hubbard U correction is applied to Nb 4d state with U= 11 eV and the corrected band gap obtained is 3.771 eV. LiNbO3 doped with Mn shows a reduction in the band gap energy which is 1.9889 eV. The dielectric constant and refractive index of LiNbO3 and Mn-doped LiNbO3 are also calculated. The optical absorption results suggest there is a shift in the absorption edge towards the visible region in comparison with the LiNbO3. The improvement in band gap and optical absorption in Mn-doped LiNbO3 making it a promising material for photovoltaic and photocatalysis applications.

Band Gap and Polarization Tuning of Ion-Doped XNbO3 (X = Li, K, Na, Ag) for Photovoltaic and Energy Storage Applications

“…Zheng et al [ 38 ], Ait brahim [ 39 ] and Maarouf et al [ 12 ] reported a reduced in Fe-doped LNO and KNO, too. We also obtain this behavior for other TM ions with ionic radius smaller than that of Nb in qualitative agreement with the experimental data of Maarouf et al [ 12 ] for KNO and of Liang et al [ 14 ], Mamoun et al [ 40 ], and Zainuddin et al [ 41 ] for LNO. The results indicate that the band gap is significantly narrowed for all the transition metal-doped LNO and KNO.…”